4. CONTAMINATION
• The presence of an infectious agent on a body surface
• Contamination on a body surface does not imply a
carrier state
• Pollution : the presence of offensive, but not necessarily
infectious matter in the environment
5. The lodgement, development and reproduction of
arthropods on the surface of the body or in the
clothing
INFESTATION
6. HOST
• A person or other animal, that affords lodgement to an
infectious agent under natural conditions
• Obligate host : the only host
• Eg: Man in measles & typhoid fever
7. HOST
• Primary or definitive host: hosts in which the parasite
attains maturity or passes its sexual stage
• Secondary or intermediate hosts: the parasite is in a
larval or asexual state
• Transport host is a carrier in which the organism
remains alive but does not undergo development
10. COMMUNICABLE DISEASE
An illness due to a specific infectious agent
or its toxic products capable of being directly or indirectly
transmitted from man to man, animal to animal, or from the
environment to man or animal
Eg: Varicella, Polio
12. Endemic
• The constant presence of a disease or infectious agent
within a given geographic area or population group
without importation from outside
• When conditions are favourable may burst into an
epidemic
• Eg:Hepatitis A,Typhoid fever,Leptospirosis,Common
cold
13.
14. • Hyperendemic: the disease is constantly present at a
high incidence and/or prevalence rate and affects all age
groups equally
• Holoendemic: a high level of infection beginning early
in life and affecting most of the child population,
leading to a state of equilibrium such that the adult
population shows evidence of the disease much less
commonly than do the children
Eg: Malaria
15.
16. SPORADIC
• Scattered about
• The cases occur irregularly haphazardly from time to
time, and generally infrequently
• May be the starting point of an epidemic
• Eg: Polio, Tetanus, Herpes zoster, Meningococcal
meningitis
• Many Zoonotic diseases are characterised by sporadic
transmission to man
17. PANDEMIC
• An epidemic usually affecting a large proportion of the
population
• Eg: Influenza pandemics of 1918 and 1957,
• Cholera El Tor in 1962
• Acute haemorrhagic conjunctivitis in 1971 and 1981
18.
19. EXOTIC
• Diseases which are imported into a country in which
they do not otherwise occur
• Rabies in UK
• Epidemic Polyarthritis in
– visitors to Fizi,
– due to ross river virus
21. • Anthropozoonoses : infections transmitted to man from
vertebrate animals,
Eg: Rabies, Plague, Hydatid disease, Anthrax
• Zooanthroponoses :infections transmitted from man to
vertebrate animals.
Eg: Human Tuberculosis in cattle
• Amphixenoses :infections maintained in both man and
lower vertebrate animals that may be transmitted in
either direction
Eg: T.Cruzi, S.Joponicum
22. • EPIZOOTIC: An outbreak
(epidemic) of disease in an animal
population
Eg: Anthrax, Brucellosis, Rabies,
Influenza, Q fever
• EPORNITHIC: An outbreak
(epidemic) of disease in a bird
population
• ENZOOTIC: An endemic
occurring in animals
Eg: Anthrax, Rabies, Brucellosis,
Bovine tuberculosis,
23. NOSOCOMIAL INFECTION
• An infection originating in a patient while in a hospital
or other health care facility
• Not present or incubating at the time of admission
• Not the residual of an infection acquired during a
previous admission
• Includes infections acquired in the hospital but
appearing after discharge
• Eg: Surgical wounds, Hepatitis B and Urinary tract
infections.
24.
25. OPPURTUNISTIC INFECTION
• Infection by an organism that takes the opportunity
provided by a defect in host defence to infect the host
and hence cause disease
• Herpes simplex, Cytomegalouirus, Toxoplasma,
M.Tuberculosis, M.Avium intracellulare, Pneumocystis
26. IATROGENIC (PHYSICIAN INDUCED)
DISEASE
Any untoward or adverse
consequence of a preventive, diagnostic or
therapeutic regimen or procedure, that cause
impairment, handicap, disability or death
resulting from a physician's professional
activity or from the professional activity of
other health professionals
27. • Disease may be serious enough to prolong the hospital
stay, require special treatment or actually threaten life
• Reactions to penicillin,
• childhood leukaemia due to prenatal x-rays,
• hepatitis B following blood transfusion
• These are all preventable
29. ERADlCATlON
• Termination of all transmission of infection by
extermination of the infectious agent through
surveillance and containment
• Absolute process, an "all or none" phenomenon
• Eg: Smallpox
• Diseases which are amenable to eradication are measles,
diphtheria, polio and guinea worm
Editor's Notes
The lodgement, development and reproduction of arthropods on the surface of the body or in the clothing
Eg: Lice, itch mite
Invasion of the gut by parasitic worms
Eg: Ascariasis
Cat lung worm –snail (IMH)-cat (DH)-mouse (TH)
Direct transmission: direct contact, droplet ,trans placental (kissing,skin to skin,sexual),direct contact with substances harbouring infectious agent
Indirect: vector born,vehicle borne, air borne,water
The "unusual" occurrence in a community or region of disease, specific health-related behaviour or other health-related events clearly in excess of "expected occurrence".
The modern "slow" epidemics of non-communicable diseases eg: CHD, lung cancer
Epidemic threshold: arbitrary limit of two standard errors from the endemic frequency
An infection or infectious disease transmissible under natural conditions from vertebrate animals to man
Denotes a NEW disorder associated with being in the hospital
The continuous scrutiny the factors that determine the occurrence and distribution of disease and other conditions of ill health
Essential for effective control and prevention
Includes the collection, analysis, interpretation and distribution of relevant data for action
Main purpose is to detect changes in trend and distribution of disease in order to initiate investigative or control measures